<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style type="text/css">
        div{
            color: aquamarine;
            /*width也可以用百分比表示如50%，即占页面宽50%
            */
            width: 300px;
            height: 100px;
            /*dashed 虚线
               solid 实线
            */
            border:1px dashed blue;
        }
    </style>
</head>
<body>
<div>sdasdasdsadsada</div>
</body>
</html>